U.S. Pat. No. 4,312,101 discloses a hose clamp which, after having been applied to the hose/nipple connection to be sealed, is tightened by deforming an ear provided in the clamp. To prevent the hose from entering the ear during tightening and thereby being lifted off the nipple, the known hose clamp is provided with an insert made of band material which is inserted into the clamp so as to bridge the gap of the ear.
While an easily deformable steel according to DIN 1.4301 having a typical thickness of 0.6 mm is used for normal hose clamps, specifically clamps of the above-described type with an ear that is to be tightened, inserts are made of an essentially thinner material, typically steel according to DIN 1.4310 with a thickness of 0.2 to 0.4 mm which has high resiliency and high stiffness, is correspondingly difficult to deform and is therefore unsuited for ear clamps. The steels DIN 1.4301 and 1.4310 are defined in European standard DIN EN 10088-2 dated Aug. 1995.
The present invention is based on the idea that a band material, which is typical with such inserts for known hose clamps, is used for manufacturing the hose clamps themselves. In this way, the same starting material is used for an additional purpose, resulting in a saving of cost. In doing so, it is principally possible that finished inserts, which are intended for use with known hose clamps and are cut and formed to the shape provided therefore, are employed for making hose clamps according to the invention.
The embodiment wherein the material of the band ring is steel according to DIN 1.4310 having a thickness of 0.2 to 0.3 mm and wherein the band ring has border regions raised outwardly from a center portion that takes a substantial part of the band width is advantageous for the stiffness of the hose clamp. Having the center portion of the band ring provided with a curved cross-section or having the center portion of the band ring provided with an outwardly convexly curved cross-section provides a hose clamp with an intrinsic prestress which is not only advantageous for compensating tolerances but also ensures the hose clamp to resiliently engage the hose when the hook in inserted in the opening.
Having the outer overlapping band end of the open band ring have its terminal edge chamfered in the areas of raised border regions results in the hose clamp being easy to close.
Having the hook partially punched and pressed out of the band material wherein the hook in the closed condition projects beyond the plane portion of the band ring no further than the outwardly raised border regions results in a hose clamp of low profile without any parts projecting far radially outwardly.
A typical field of application of the hose clamp according to the invention is where the hose clamps have a diameter of up to 20 mm, preferably 3 to 13 mm, wherein the band material has a width of 5 to 12 mm, preferably 8 mm, and a thickness of at most 0.4 mm, preferably 0.3 mm.
A tool for closing a hose clamp which consists of an open band ring having overlapping ends, an opening located in one band end and a hook located in the other band end for engaging the opening, specifically for closing the hose clamp wherein the tool is formed as a pair grippers with two jaws which in the closed condition form an inner surface having a diameter corresponding to the outer diameter of the closed hose clamp and wherein the inner surfaces of the jaws form a smooth cylindrical surface over their substantial width with enlarged border regions is particularly suited for closing the hose clamp according to the invention. This tool permits performing the closure by means of a simple gripper movement with the hook engaging the opening.
Having the jaws of the tool form a substantially uninterrupted inner surface in the closed condition and having the jaws be exchangeable in accordance with the diameter of the respective hose clamp are suitable measures to ensure a uniform closure of the hose clamp to a cylindrical ring.
Having the tips of the jaws overlap each other in the closed condition and having the tips of the jaws have their widths reduced to substantially one-half, ensures that the hose clamp is engaged by the tool over its entire circumference.
Wherein, in the hinge region, one gripper arm is formed by two legs, with the other gripper arm crossing between the two legs or wherein the tip of one jaw has two outer tines between which a central tine formed at the tip of the other jaw engages in the closed condition of the grippers, are of advantage in that they safely prevent canting during closure, which could result in deviations of the finished, closed hose clamp from the cylindrical shape.
A preferred embodiment of the invention will now be explained in more detail with reference to the drawings.